1. Field of the Invention
The present invention relates to an optical connector plug that detachably connects with a connector receptacle or adapter in a connector for an optical cable, and more particularly, to a shading member-equipped optical connector plug provided with means to block light from an optical fiber cable.
2. Related Art
Conventionally, in optical communications, since the power of the light source increases as the optical communication volume increases, looking directly into an optical signal while connecting an optical connector can damage the eye. Further, in recent years, with the introduction of optical communications-based Internet in companies and homes, the opportunities for ordinary people other than specialists to come into contact with optical connector plugs has increased, and with it the danger of looking directly into an optical signal and suffering consequent eye damage. Moreover, it is also necessary to protect the end of an optical cable from contamination by dirt and the like. Consequently, a shutter has come to be provided on optical connector plugs as eye protection means as well as dust protection means.
For example, in an optical connector described in JP-A-07-333454, a movable member is provided on an outer periphery of a connecting front surface side of an optical connector to which an optical cable is connected, and a cap member composed of a plurality of cap pieces is connected to a front surface side of the movable member by an opening/closing shaft. This opening/closing shaft is urged in a direction in which the cap pieces close, which enables the cap pieces to move in a direction of a diameter in conjunction with a sliding of the movable member with respect to the optical connector so as to open and close.
In addition, an optical fiber connector described in JP-A-2005-092082 comprises a plug shutter unit, which in turn comprises a movable cylinder, a shutter door, and an engagement piece. The shutter door is opened and closed in accordance with the movement of the movable cylinder. The engagement piece engages an engagement hook on a connector receptacle side and the movable cylinder is moved together with the connector receptacle. Then, when the optical finer plug is drawn out from the connector receptacle, the movable cylinder is moved by itself and the shutter door is closed.
However, in the invention described in JP-H07-333454-A, after the plug is engaged with the connector receptacle, even when such plug is removed the movable member does not automatically return to its original position, and therefore there is a risk that a worker might look directly into the light Moreover, in the invention described in JP-A-2005-092082, although there is an automatic return means for the shutter, a specialized engagement piece is used for that return means, and accordingly it cannot be used as is with conventionally existing optical connector plugs. Further, although a method that uses a biasing means as the return means for the movable member is shown, that biasing means appears on the outside of the plug, which vitiates its operability and increases the likelihood of a malfunction due to the sandwiching of foreign matter therewithin. Indeed, any structure that covers the body of the plug with a housing intended as a shutter increase the overall size of the plug, which makes it unsuitable for high-density mounting and in which the plug engagement piece is completely covered by the housing, which makes it difficult to guide and complicates fitting when inserting the plug into another connector receptacle.